1. Field of the Invention
The present invention is in the field of high-fidelity audio systems and specifically relates to apparatus for cancelling spurious signals which might appear on the conductors connecting the power amplifier to a remotely-located speaker system.
2. The Prior Art
In prior art high fidelity sound producing or reproducing systems a nearly perfectly amplified representation of an audio input signal is generated at the power amplifier output terminals. However, modern loudspeaker systems frequently present a very complex load condition to the amplifier through speaker wires and connectors of finite resistance and impedance. These complex load conditions result from the variations in phase angle and impedence components of resistance, capacitance and inductance with frequency and amplitude changes. Many high fidelity speaker systems employ very complex cross-over networks between the various transducers with the result that spurious signals may be applied to all of the transducers. It should be noted that were the impedance seen by the speaker at its terminal zero in magnitude no spurious signal could be developed. Also, loudspeaker wires as normally employed in prior art high fidelity sound systems are not capable of delivering a perfect reproduction of an amplifier output signal to even a perfectly resistive load (which is practically never encountered) by reason of the capacitive and inductive reactance properties of such interconnecting wires or cables.